A Miami Beach police detective is under investigation after an altercation with a drunk model and a man who claims we was just trying to be a Good Samaritan — only to be rewarded with a kick in the head and being knocked unconscious.

Detective Philippe Archer arrested 29-year old Megan Adamescu and 50-year old Andrew Mossberg on June 26 outside a South Beach condo on West Avenue. The moments leading up the arrest are in dispute by Adamescu, Mossberg and what’s written in Archer’s arrest forms, as first reported in the Miami New Times.

Archer is now the subject of an internal affairs investigation, according to police spokesman Sgt. Bobby Hernandez.

The state attorney’s office has so far declined to file charges against Adamescu and Mossberg, although that could change, said State Attorney’s Office spokesman Ed Griffith.

The allegations against Archer once again bring unfavorable attention to the Miami Beach Police Department, which has been trying to shed a reputation for rough handling of perpetrators — including this month’s Tasering of a teenage graffiti artist that ended in his death.

Archer is one of about a dozen Miami Beach and Hialeah officers who, during the 2011 Memorial Day weekend, fired more than 100 bullets at a drunk motorist, killing him.

In the most recent controversy to come to light:

According to the arrest forms, Adamescu was drunk and refused to leave the lobby of the South Bay Club condo. Detective Archer was a block away, conducting an undercover narcotics investigation, when he responded to a call from the concierge of the condo. He was in plain clothes and an unmarked car.

The concierge, Adrian Aponte, said he called police multiple times because Adamescu refused to leave the lobby and fell asleep “from drunkenness” on a couch. When Aponte picked up the phone to call for help, he said Adamescu yanked it from his hand and threw it at his chest.

“After about half an hour, I called police a third time and an undercover officer came. He identified himself to us...He always said he was a police officer. He asked her to leave the property,” Aponte said.

She walked out, Aponte said.

Once outside, Archer asked Adamescu for identification, according to his arrest report. Adamescu “was so intoxicated that she could not retrieve her I.D. after numerous attempts,” the arrest form written by Archer states. “I removed her purse from her person and retrieved her passport.”

That’s when Andrew Mossberg, who lives nearby, happened to walk by with his 12-year-old son and beagle-mix named Snoopy, said his lawyer, Edward O’Donnell.

The lawyer said Mossberg thought he was witnessing a purse snatching.

So Mossberg called the non-emergency police line and yelled to Archer that police were on the way, O’Donnell said.

“That’s when he ran at me, kicked me once in the left side of the head, then kicked me again in the forehead, and punched me twice,” Mossberg told the New Times.

Mossberg’s mug shot, available online, shows a bruise in the shape of a shoe print in his forehead and a scrape toward the back of his bald head. His nose and right cheek are scraped.

Adamescu’s attorney, Menachem Mayberg, said his client also thought her purse was being stolen. She was unaware that Archer was a police officer, Mayberg said.

“All she wanted to know was who it was who was grabbing her purse and her passport,” Mayberg said.

In the arrest forms, Archer, who is black, claims that Adamescu used racial slurs and repeatedly tried to “snatch” her passport out of the detective’s hands. Archer also wrote that Mossberg “began to interfere with the ongoing investigation,” which distracted him. Archer writes in his report that Adamescu then slapped him in the face, “knowing that I was a L.E.O,” which stands for law enforcement officer.

“I immediately countered with an open hand strike,” Archer wrote.

Adamescu fell backwards and hit her head, according to the arrest report. That’s when Mossberg “charged me, preparing to attack me,” Archer wrote. “I told him to stop, at which time I conducted a front kick to his abdomen area, causing him to step back,” the arrest report said.

Mossberg — who is 5’2 and weighs 118-pounds, according to a police report — came at Archer a second time, the detective wrote.

“I then conducted a round kick which initially struck him on the shoulder. As [Mossberg] attempted to avoid that kick, it followed through striking him on the right side of the face,” Archer wrote.

The two engaged a third time, Archer wrote, and Mossberg threw his police radio into some shrubs. The detective brought Mossberg to the ground, but in the process, Mossberg hit the detective’s Nissan Pathfinder, the arrest report said. Miami Beach’s police union president says Mossberg was KO’d in the course of hitting the car, though the arrest form makes no mention of Mossberg ever being unconscious.

Alex Bello, the union president, said that Archer told him after the incident that the detective lifted his shirt to reveal his badge.

“He says that he said several times, ‘How many times did I tell you that I’m a police officer?’ ”